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Fed [463]
3 years ago
13

A 5.0 g sample of calcium nitrate (Ca(NO3)2, M = 164) contaminated with silica (SiO2, M = 60.1) is found to contain 1.0 g calciu

m. What is the mass percent purity of calcium nitrate in the sample?
Chemistry
1 answer:
zhenek [66]3 years ago
4 0

Answer:

= 82%

Explanation:

Percentage purity is calculated by the formula;

% purity = (mass of pure chemical/total mass of sample) × 100

In this case;

1 mole of Ca(NO3)2 = 164 g

but; 164 g of Ca(NO3)2 = 40 g Ca

Therefore; mass of Ca(NO3)2 = 164 /40

                                                  = 4.1 g

Thus;

% purity of Ca(NO3)2 = (Mass of Ca(NO3)2/ mass of the sample)× 100

                                    = (4.1 g/ 5 g) × 100

                                    = 82%

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The two methods in the lab for measuring the volume of a geometric solid object are weighing it on the balance and measuring it
Yakvenalex [24]

Answer:

Measuring with a ruler and using final volume minus initial volume

Explanation:

You can measure the volume of a geometric object by measuring its sides with a ruler and calculating the volume according to the corresponding formula for each object. For example, for a rectangular prism it would be

volume=length*width*height

You can also measure the volume of an object by measuring how much water it displaces. To do this you have to fill a measuring cylinder with enough water for the object to be completely submerged and take note of the volume. Then, add the object and note again the volume of the water+object. The difference between both is the volume of the object.

Volume of the object= volume of water and object - volume of water

The advantage of the second method is that it can be used for objects with irregular shapes as long as they do not float.

8 0
3 years ago
A molecule contains five atoms and has a molecular weight of 85 g per mole. the atoms are of elements with atomic numbers 1, 6,
inessss [21]

Answer:

            Dichloromethane

Explanation:

As we know the atomic number given belongs to following elements, i.e.

Atomic #                   Element                      M.Mass

   1                           Hydrogen                    1 g.mol⁻¹

   6                          Carbon                        12 g.mol⁻¹

   17                         Chlorine                      35.5 g.mol⁻¹

Also the molecular formula of Dichloromethane is,

                           =  CH₂Cl₂

Putting molar masses of each element,

                          =  (12)₁  +  (1)₂  +  (35.5)₂

                          =  12  +  2  +  71

                          =  85 g.mol⁺¹

Result:

         Hence the only possible structure containing 5 atoms is Dichloromethane.

6 0
3 years ago
I need help answering this question
ohaa [14]
The correct answer is c because enzymes increase the rate of all biochemical processes
4 0
3 years ago
Read 2 more answers
What phase of matter changes volume when moved from one container to another ?
Sever21 [200]

Answer:

gas

Explanation:

6 0
3 years ago
Read 2 more answers
Question 3 0
Tanya [424]

Answer:

Option D. KBr < KCl < NaCl

Explanation:

We'll begin by calculating the number of mole of each sample.

This can be obtained as follow:

For NaCl:

Mass = 1 g

Molar mass of NaCl = 23 + 35.5 = 58.5 g/mol

Mole of NaCl =?

Mole = mass /Molar mass

Mole of NaCl = 1/58.5

Mole of NaCl = 0.0171 mole

For Kbr:

Mass = 1 g

Molar mass of KBr = 39 + 80 = 119 g/mol

Mole of KBr =?

Mole = mass /Molar mass

Mole of KBr = 1/119

Mole of KBr = 0.0084 mole

For KCl:

Mass = 1 g

Molar mass of KCl = 39 + 35.5 = 74.5 g/mol

Mole of KCl =?

Mole = mass /Molar mass

Mole of KCl = 1/74.5

Mole of KCl = 0.0134 mole

Summary

Sample >>>>>>>> Number of mole

NaCl >>>>>>>>>> 0.0171

KBr >>>>>>>>>>> 0.0084

KCl >>>>>>>>>>> 0.0134

Arranging the number of mole of the sampl in increasing order, we have:

KBr < KCl < NaCl

5 0
3 years ago
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